THE mystery of Easter Island’s magnificent looming moai stone heads has finally been solved, scientists have said. So what is the secret?

For centuries, the purpose of the massive stone statues has remained one of ancient humanity’s best-kept secrets. The Easter Island moai heads have beguiled explorers, researchers, experts and travellers to the remote Chilean island in Polynesia. The gargantuan heads, dotted around the island, date back to the period 1100–1680 AD and are mostly carved out of a soft volcanic rock called Tuff.

Related articles

Many things about the heads puzzled scientists: how, before modern technology, were the mammoth stones moved around the island? Why were they placed where they were? And what is their purpose?

Now, experts think they have some answers: the statues are located strategically to point the way to drinkable water.

Researchers say they have analysed the locations of the megalithic platforms, or ahu, on which many of the moai sit, as well as scrutinising sites of the island’s resources, and have discovered the structures are typically found close to sources of fresh water.

They say the finding backs up the idea that aspects of the construction of the platforms and statues, such as their size, could be tied to the abundance and quality of such supplies.

Professor Carl Lipo from Binghamton University in New York, who was a co-author of the research, said: “What is important about it is that it demonstrates the statue locations themselves are not a weird ritual place.

“They represent ritual in a sense of there is symbolic meaning to them, but they are integrated into the lives of the community.”

Easter Island, or Rapa Nui, has more than 300 megalithic platforms, each of which might have been made by a separate community.

The monuments are thought to represent ancestors and were linked to ritual activity, forming a focal point for communities.

Easter Island: Researchers say they have analysed the locations of the megalithic platforms, or ahu (Image: Getty)

The potential for the heads to be correlated with key resources has been suggested, but this latest study is the first attempt to prove it.

The team focused on the east of the island, where various resources have been well mapped, and looked at the distribution of 93 megalithic platforms constructed before European sailors turned up in the 18th century.

After finding no link to the proximity of rock used for tools or for the monuments, they looked at whether the ahu were found near other important resources: gardens spread with stones in which crops like sweet potatoes were grown, sites linked to fishing, and sources of fresh water.

The team investigating focused on where those living on Rapa Nui got their drinking water from.

The island has no permanent streams, and there is little evidence that residents relied on the island’s lakes.

Easter Island: The statues are located strategically to point the way to drinkable water (Image: Getty)

However, fresh water passes through the ground into aquifers, seeping into caves as well as emerging around the coast.

Professor Lipo said: “It is sort of amazing at low tide when the water goes down, suddenly there are streams running off at different spots right at the coast that are just pure fresh water.

“We noticed this, actually, when we were doing a survey on the island, that we would see horses drinking from the ocean.”

The results of the new research, published in the journal Plos One, reveal proximity to freshwater sites is the best explanation for the ahu locations – and explains why they crop up inland as well as on the coast.